La vitesse de marche ralentie chez les hommes âgés améliore capacité la génération de la force du triceps sural

Traduction: G.M.

Med Sci Sports Exerc. 2016 Jul 27.

Slower Walking Speed in Older Men Improves Triceps Surae Force Generation Ability

Stenroth L¹, Sipilä S, Finni T, Cronin NJ.

Author information

• ¹1University of Jyvaskyla, Neuromuscular Research Center, Department of Biology of Physical Activity, Jyvaskyla, Finland; 2University of Jyvaskyla, Gerontology Research Center and Department of Health Sciences, Jyvaskyla, Finland.

Abstract

PURPOSE:

Older adults walk slower than young adults but it is not known why. Previous research suggests that ankle plantarflexors may have a crucial role in the reduction of walking speed. The purpose of this study was to investigate age-related differences in triceps surae muscle-tendon function during walking to further investigate the role of plantarflexors in the age-related reduction of walking speed.
Les personnes âgées marchent plus lentement que les jeunes adultes, mais on ne sait pas pourquoi. Des recherches antérieures suggèrent que les fléchisseurs plantaires de la cheville peuvent avoir un rôle crucial dans la réduction de la vitesse de marche. Le but de cette étude était d'étudier les différences liées à l'âge dans la fonction de muscle-tendon du triceps lors de la marche pour étudier davantage le rôle des fléchisseurs plantaires dans la réduction de la vitesse de marche liée à l'âge.

METHODS:

Medial gastrocnemius and soleus muscle fascicle lengths were measured using ultrasound imaging during walking from 13 young (25±4yrs) men at preferred walking speed, and from 13 older (73±5yrs) men at preferred speed and at the young men's preferred speed. Muscle-tendon unit lengths were calculated from joint kinematics and tendinous tissue lengths were calculated by subtracting muscle lengths from muscle-tendon unit lengths. In addition, ground reaction forces and electromyographic activity of medial gastrocnemius and soleus were measured.

RESULTS:

In both medial gastrocnemius and soleus it was observed that at preferred walking speed, older men used a narrower muscle fascicle operating range and lower shortening velocity at the estimated time of triceps surae peak force generation compared to young men. Fascicles also accounted for a lower proportion of muscle-tendon unit length changes during the stance phase in older compared to young men. Significant differences in triceps surae muscle function were not observed between age groups when compared at matched walking speed.

CONCLUSIONS:

In older men, walking at preferred speed allows triceps surae muscles to generate force with more favorable shortening velocity and to enhance use of tendinous tissue elasticity compared to walking at young men's preferred speed. The results suggest that older men may prefer slower walking speeds to compensate for decreased plantarflexor strength.
Chez les hommes âgés, la marche à vitesse préférée permet aux muscles du triceps de générer la force avec une vitesse de raccourcissement plus favorable et d'améliorer l'utilisation de l'élasticité des tissus tendineux par rapport à la marche des jeunes hommes à leur vitesse préférée . Les résultats suggèrent que les hommes plus âgés peuvent préférer des vitesses de marche plus lentes pour compenser la diminution de la force des fléchisseurs plantaires.

PMID: 27471788